1. Field of the Invention
The present invention relates to a heat exchanger core of a plate type which joins the peripheral edges of a pair of metal plates to make up an element part.
2. Description of the Related Art
A conventional plate-type heat exchanger core has been completed by bending an elongated metal plate by press working to form a multiplicity of recessed and raised portions or corrugated portions on the surface, preparing a pair of plates each having ports formed at both ends in the longitudinal direction, joining the peripheral portions of the pair of plates by brazing or welding to make up elements, and coupling the elements at their ports with each other in a liquid-tight manner.
Inconveniently, such a plate-type heat exchanger has necessitated a large number of plates resulting in an increase of the number of the constituent parts, and troublesome and time-consuming assembly.
In addition, the brazing or welding had to be effected along the full peripheral edges of the plate, resulting in an increased number of joints, which may often cause any leaks.
It is therefore the object of the present invention to solve the above problem.
According to a first aspect of the present invention there is provided a heat exchanger core comprising a multiplicity of flat plate parts formed by alternately folding back a single belt-like metal plate in zigzag at a first fold-back edge and at a second fold-back edge; a plurality of element parts formed by joining peripheral edges of a pair of adjoining flat plate parts which are integrally coupled to each other at the first fold-back edge, adjoining ones of the plurality of element parts being integrally coupled at a certain interval to each other at the second fold-back edge; and a pair of ports for a first fluid formed at positions apart from each other at the peripheral edge of each of the plurality of element parts, wherein a second fluid flows through the outer surface side of the plurality of element parts.
The planar surface of each of the multiplicity of flat plate parts is preferably bent into a corrugation, with the pair of ports of each element part being formed at the second fold-back edge.
Preferably, the heat exchanger core further comprises a manifold part associated with the ports, the manifold part extending from the second fold-back edge to the first fold-back edge or its vicinity.
The manifold part may be bent into a corrugation such that the amplitude of the corrugation is smaller than the amplitude of corrugations of the other parts.
The planar surface of each of the multiplicity of flat plate parts may be bent into a corrugation, with one of the pair of ports of each element part being formed at the second fold-back edge, with the other of the pair of ports being formed at the edge of a side orthogonal to the side thereof.
According to a second aspect of the present invention there is provided a heat exchanger core comprising a multiplicity of flat plate parts formed by alternately folding back a single belt-like metal plate in zigzag at a first fold-back edge and at a second fold-back edge; a plurality of element parts formed by joining peripheral edges of a pair of adjoining flat plate parts which are integrally coupled to each other at the first fold-back edge, adjoining ones of the plurality of element parts being integrally coupled at a certain interval to each other at the second fold-back edge; and a pair of ports for a first fluid formed at positions apart from each other on the planar surface of each element part, the pair of ports of each element part being connected to each other such that the pair of ports communicate with each other in the thickness direction, wherein a second fluid flows through the outer surface side of the plurality of element parts.